where \(\delta {\phi }={\phi }-{\phi }_{\text{v}}\) 
is the difference between soliton field (REF ) and the vacuum field
\({\phi }_{\text{v}} = \left( 0,0,-1\right)\) .
The known condition of applicability of the Born approximation [1]}
has the form \(\left|V_{\text{int}} \right|\ll pa/\left(m_{\psi }a^{2}\right)\) , where \(p\)  is the momentum of the fermion, \(m_{\psi }\)  is its mass, and
\(a\)  is the size of the area in which the fermion-soliton interaction is
markedly different from zero.
In our case, this condition can be written as
\(h^{2}r_{0} \ll p, \) 
